Model output discussion - 5th December 2016 - Into Winter we go

[doghouse]

2 minutes ago, Frosty. said:

But the models are showing snow later next week, happy days!

Wish it were true Frosty, but it'll be gone as quick as it came,  and then rearrange the following words into a popular expression, gun, mild, looking and barrel 

[mulzy]

3 minutes ago, doghouse said:

Wish it were true Frosty, but it'll be gone as quick as it came,  and then rearrange the following words into a popular expression, gun, mild, looking and barrel 

Steve Murr summed it up perfectly - grim!

Edited December 17, 2016 by mulzy

[johncam]

We had more snow last Dec up here in central Scotland, looks mostly mild andf getting milder if the high ends up back over europe with winds turning to the sw

[Singularity]

The tropical convection is threatening to stick around Indonesia (5/6 phase borders) for a while before getting on with eastward propagation. This I believe is a similar setup to what fueled the exceptionally stormy run of weeks in 2013/14 so I for once sincerely hope the convection gets a move on eastward and as soon as possible. GEFS is the best of a bad bunch in that respect. The det. didn't follow suit (or should that be suite - ha) though; GFS 12z spent some 5 days longer near the 5/6 border.

There are also signs of the polar vortex displacing toward the eastern N. Atlantic which will only exacerbate any stormy setups should connection with the troposphere occur (not a given).

A possible silver lining from the setup is that if the blocking can fight hard enough, the intense pressure gradients between it and the storms will drive a lot of air into the Scandinavian mountain ranges, which could generate some wave action on the stratosphere to accompany what's showing up on the Pacific side. Then we have the coveted wave 2 formation.

Signs are anything we do achieve could hit the stratosphere top-down which would be a good way to blow apart the strong (yet displaced) vortex at 10 hPa.

All this takes time and it could well be that Dec will continue to do everything it can to be the ultimate 'troll month' in which relatively small adjustments to the longwave pattern could produce much more seasonal conditions or even colder than average temperatures, yet time and time again the background forcing refuses to play ball and give us even that little bit of consolation. If the MJO signal moved more toward the 6/7 border than 5/6 we'd possibly see quite a change in fortunes - I know the composites are only a loose guide but the anomalies pretty much invert themselves in our vicinity when looking from 5 to 7.

    

If you believe in parallel realities, it's probably not a lot of steps toward one that features mid-lat blocking for mid-Dec and high-lat blocking for late Dec. Finding out we're in this reality instead has hurt pretty bad, but not as much as would have been the case had HLB been the signal for mid-Dec when one might dare to have more confidence in it.

[IDO]

30 minutes ago, gottolovethisweather said:

Happy Christmas to you too, I'm Dreaming Of A White Christmas.  You're surely too wise (like all of us old-timers), to write off prospects of some transient snowfall come the festive period, especially given we are talking timeframes of t+19,000 minutes or thereabouts. Yet, you did cleverly present an argument for all options being on a table, I say it a few more days of model runs before jumping on board, the nothing festive happening train. BTW I do think the 22nd into the 23rd December holds some wintry interest for a few as this period has held firm as being that way over a number of outputs now.

 

Happy Christmas to everyone else too. Off out shortly, the ECM will likely restore some faith for coldies. 

I would not rule out some flakes above 300 metres in the Scottish highlands but for 99.9% of us not very useful!

As for Dec 22-23rd wintry'ness, the Manchester GEFS suggest 15% chance, so yes maybe, but its borderline at best and any downgrade, and at this range to be expected, will just mean cold rain

:

 

Happy Christmas

Edited December 17, 2016 by IDO

[Frosty.]

6 minutes ago, nick sussex said:

Lol! I'm sure the mountain goats will be happy. It's a blink and you'll miss it affair with the flow modified and really three hours of slush on a hill is scraping the bottom of a barrel. It's a shame the models couldn't have at least managed a northerly toppler. Indeed recent years haven't even managed one of those. Maybe the ECM can pull a Christmas Cracker this evening and stop the thread turning into a wake.

I'm just looking for positives Nick, and the first snow of the winter is being shown later next week with wintry showers and transient frontal snow, especially on hills in the north. It all ties in with met office thinking with alternating milder / colder interludes before high pressure returns for the new year. 

[stewfox]

1 minute ago, IDO said:

I would not rule out some flakes above 300 metres in the Scottish highlands but for 99.9% of us not very useful!

As for Dec 22-23rd wintry'ness, the Manchester GEFS suggest 15% chance, so yes maybe, but its borderline at best and any downgrade, and at this range to be expected, will just mean cold rain.

Happy Christmas

But the GFS is still holding onto some modified PM air and some places might get snow xmas eve into early xmas day

Ok the snowman wont be the best , but some may get a chance , if they start to build 2am xmas day before the mild air kicks in ?

Supporting pic attached

 

 

[Banbury]

What GFS was showing for Xmas day 8 days ago

And in 8 days time GFS thinks Xmas day will be

Be interesting to see what the day actually brings

[frosty ground]

Looks cold to me.... especially Ireland

[stewfox]

5 minutes ago, Banbury said:

What GFS was showing for Xmas day 8 days ago

And in 8 days time GFS thinks Xmas day will be

Be interesting to see what the day actually brings

Can you compare the same model ? So all to play for.

 

[Summer Sun]

Still looking stormy on Xmas day

Edited December 17, 2016 by Summer Sun

[bradymk]

Pretty grim output overall for next 10 days at least.

However, ECM does show snow showers Ireland and Northern Ireland on Christmas Eve and probably western hills of England and Wales too. Not great I know if you don't live on a hill but crumbs....

Massive +NAO/+AO coming up, but just remember this isn't always a bad thing if it is "temporary" and change does come down the line. 

[knocker]

41 minutes ago, Singularity said:

The tropical convection is threatening to stick around Indonesia (5/6 phase borders) for a while before getting on with eastward propagation. This I believe is a similar

There are also signs of the polar vortex displacing toward the eastern N. Atlantic which will only exacerbate any stormy setups should connection with the troposphere occur (not a given).

 

I

I'm not sure whart time frame you are considering but there seems to continuing indications of the trop vortex consolidating over N. Canada with height rises adjacent to the UK which seems also to be favored in the lower Strat.

Edited December 17, 2016 by knocker

[Captain Shortwave]

ECM predicting an over-indulgence of Brussels sprouts this Christmas.

Yeah try again models.....

Christmas eve looks fairly chilly with a brisk west/north west wind with snow down to modest levels.

[Summer Sun]

Remaining unsettled on boxing day but the winds ease a fair bit colder air brings the chance of snow again

[Nick L]

Tonight's EC would bring dangerous winds across the Central Belt for Christmas Day. Gusts around 100mph, not good, dangerous stuff.

[feb1991blizzard]

Just now, Nick L said:

Tonight's EC would bring dangerous winds across the Central Belt for Christmas Day. Gusts around 100mph, not good, dangerous stuff.

Lets hope it tracks a bit further south to bring Northern England into the firing line.

[knocker]

2 minutes ago, Nick L said:

Tonight's EC would bring dangerous winds across the Central Belt for Christmas Day. Gusts around 100mph, not good, dangerous stuff.

Yes indeed. That's an horrific looking chart and hopefully plenty of time to downgrade this.

[Iceberg]

Ecm also brings little belts of snow as well. A very nice meso feature on the t240 embedded in -6 850s giving snow to Scotland. 

I agree that the models could be better but dreadful they are not unless you have a high degree of imbyism. 

[Nick L]

Let's move the discussion on from "I hope this happens..." and back to the model output please!

[Captain Shortwave]

Just now, feb1991blizzard said:

I'm hoping its stays as severe but tracks such that I get the strongest winds.

Man I know Christmas TV is bad but still 

Overall the pattern looks classic zonal with a mix of milder and colder periods, temperatures coming out a little above normal mainly due to the lack of cold/frosty nights rather than anything else. The ECM tends to move low heights around as opposed to the GFS which is tending to stick with the Atlantic trough/Euro high set up until the end of time. A chance of snow perhaps over high ground and some rather wild weather at times.

[Matthew.]

Interesting chance of a wintry blast here:

[booferking]

4 minutes ago, feb1991blizzard said:

I'm hoping its stays as severe but tracks such that I get the strongest winds.

Keep it up feb1991 its like a postmortem in here its called the weather deal with it people.

Another wintery blast right at the end hard to beat.

Edited December 17, 2016 by booferking

[Summer Sun]

JMA and ECM pretty much in agreement on the depth of the low the position of it they are not

[Frosty.]

There is actually quite a lot of cold zonality on the Ecm 12z from thursday onwards with snow at times in central and northern uk, especially on hills within a very unsettled and windy period with plenty of rain too.